Dysfunction of a sphincter in the body can lead to internal damage or disease, discomfort, or otherwise adversely affect patient quality of life.
Gastroesophageal reflux disease (GIRD), for example, is a common disorder caused most commonly by frequent transient relaxations of the lower esophageal sphincter (LES). If the lower esophageal sphincter fails to function properly, stomach contents, including acid, enzymes, and bile may flow backwards into the esophagus, causing heartburn or other disease symptoms, damage to the esophagus, and the development of precancerous lesions.
Fecal incontinence is the involuntary passage of solid or liquid stool through the anal canal. This is caused most commonly by previous damage to or aging of the external and/or internal sphincter muscles in the anal canal. Secondary causes are improper sensing and control of solid or liquid stool within the rectum.
The disease states of GERD and fecal incontinence have in common a defective sphincter barrier as a mechanism of the disease. The end result is the development of GERD and fecal incontinence symptoms due to inadequate barrier function. In both GERD and fecal incontinence, inadequate barrier function can be the result of either a mechanical defect in the sphincter, a low resting pressure in the sphincter, an overly compliant sphincter, abnormal afferent nerve impulses that trigger transient sphincter relaxations, or improper sensing of and control of lumenal contents.